bobbin race assembly on old Singer 66

I have taken apart and reassembled one of these before- but for the life of me, I can't get this one apart. Should I keep trying, or were there some made that are not removable? I have the upper portions(wick holder etc) out and can see rust in the bottom of the race.

Cil

I'm a Queen.... at least my pantyhose say I am!

(proud caretaker of a magenta 221, purple 222, assorted 66's, a 301, a pink Atlas and Monarch, and Granny's 201-2.

Soak it in Tri-Flow or a penetrating oil, and like I said wiggle it. I broke the oscillating hook on my 99K, Rusty because I used too much force trying to get the bobbin case off of it. It was rusted on too.
There is a grove on the far side of the case that fits over the lip of the hook. That is where the rust is most likely causing the trouble.